I have a friend that's interested in MTurk, but she lives in Canada. I've got a few questions for those that live in Canada. Does Amazon Payments pay you in CAD or USD? Any more info on that? What about taxes? As an american I have to provide them my SSN. That's really all I can think of at the moment. Is there any other info I haven't asked for that would be useful for me to tell my friend? (Not including the general userscripts, TO, etc, etc for getting started.)
I'm sorry to say that the most important thing you'll need to tell her is that no new applications are being accepted from non-US Turkers. And I don't mean non-North American. I really mean non-US, unfortunately. Here is the most recent post about that, with the most definitive explanation we've had yet. This has been going on since late July, this year.
In answer to your questions: Canadian workers, like those everywhere in the world outside of the US and India, are "paid" in Gift Certificates in US dollars that can be redeemed (ie. used) only on the US Amazon site for merchandise. They cannot be used anywhere else, and cannot be turned into cash or used to buy gift certificates for someone else. As you can only buy stuff with your gift certificates, and have it shipped to Canada, there are no taxation issues. You will, however, need to pay customs on your purchases. Hope this helps.